1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus capable of forming an image on a recording medium by employing electrophotography.
2. Description of the Related Art
Here, the electrophotographic image forming apparatus is an apparatus configured to form an image on a recording medium by employing electrophotography. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (such as a laser beam printer and a light-emitting diode (LED) printer), and a facsimile apparatus. A process cartridge is formed by integrating into a cartridge an electrophotographic photosensitive drum and a process unit acting thereon, and is attachable and detachable to and from the image forming apparatus main body. Examples of the process unit include a charging unit acting on the electrophotographic photosensitive drum, a developing unit, and a cleaning unit.
The developing device as the developing unit included in the process cartridge mainly includes a frame storing developer, a developing roller, a supply roller supplying toner to the developing roller, and a developer regulating member configured to regulate the thickness of the developer (hereinafter, referred to as the “toner”) on the developing roller.
Here, Japanese Patent Application Laid-Open No. 2006-208689 discusses a method for mounting a supply roller on a frame in which the supply roller is mounted on the frame in the axial direction of the supply roller. According to Japanese Patent Application Laid-Open No. 2006-208689, a through-hole is formed on a side surface of the frame, and the supply roller is inserted in the axial direction from the through-hole, thereby mounting the supply roller on the frame.
In the configuration discussed in Japanese Patent Application Laid-Open No. 2006-208689, the cross section of a through-hole, through which the supply roller is inserted, is smaller than that of the supply roller, so that, when the supply roller is to be inserted into the through-hole, the peripheral surface of the supply roller is rubbed against the inner edge of the through-hole. As a result, there is a possibility that the peripheral surface of the supply roller is damaged.